Use bitmap' instead of icon->pict'

Rename `pict->icon' to `pict->bitmap' and put in `slideshow/pict'

collects/icons/main.rkt

@@ -11,8 +11,6 @@
           icon-style/c
           toolbar-icon-height
           default-icon-style
-          icon->pict
-          pict->icon
           load-icon-pict
           load-icon
           format-icon-name

collects/icons/private/svg.rkt

@@ -16,32 +16,17 @@
 (defparam toolbar-icon-height (>/c 0) 16)
 (defparam default-icon-style (or/c 'diffuse 'shiny) 'diffuse)
 
-(defproc (icon->pict [icon (is-a?/c bitmap%)]) pict?
-  (bitmap icon))
-
-(defproc (pict->icon [p pict?]) (is-a?/c bitmap%)
-  (define w (pict-width p))
-  (define h (pict-height p))
-  (define bm (make-bitmap (max 1 (inexact->exact (ceiling w)))
-                          (max 1 (inexact->exact (ceiling h)))))
-  (define dc (make-object bitmap-dc% bm))
-  (send dc set-smoothing 'smoothed)
-  (draw-pict p dc 0 0)
-  bm)
-
 (defproc (load-icon-pict [category string?] [name string?] [height (>=/c 0)]) pict?
   (define hs (icon-category-heights category))
   (define icon-height
     (let ([h  (for/first ([h  (in-list hs)] #:when (height . <= . h)) h)])
       (if h h (last hs))))
-  (define icon
+  (define icon-path
-    (make-object bitmap%
+    (build-path svg-icons-base-path (format "~a/~a/~a.png" category icon-height name)))
-      (build-path svg-icons-base-path (format "~a/~a/~a.png" category icon-height name))
+  (scale (bitmap icon-path) (/ height icon-height)))
-      'png/alpha))
-  (scale (icon->pict icon) (/ height icon-height)))
 
 (defproc (load-icon [category string?] [name string?] [height (>=/c 0)]) (is-a?/c bitmap%)
-  (pict->icon (load-icon-pict category name height)))
+  (pict->bitmap (load-icon-pict category name height)))
 
 (defproc (format-icon-name [name string?] [color icon-color/c]
                            [style (or/c icon-style/c #f) (default-icon-style)]) string?
@@ -183,7 +168,7 @@
        (syntax/loc stx
          (begin (defproc (f [color icon-color/c] [height (>=/c 0)]
                             [style icon-style/c (default-icon-style)]) (is-a?/c bitmap%)
-                  (pict->icon (f-pict color height style)))
+                  (pict->bitmap (f-pict color height style)))
                 ...)))]))
 
 (define-syntax (define-wrapped-icon-fun/no-color stx)
@@ -194,7 +179,7 @@
        (syntax/loc stx
          (begin (defproc (f [height (>=/c 0)]
                             [style icon-style/c (default-icon-style)]) (is-a?/c bitmap%)
-                  (pict->icon (f-pict height style)))
+                  (pict->bitmap (f-pict height style)))
                 ...)))]))
 
 (define-wrapped-icon-fun

collects/icons/scribblings/icons.scrbl

@@ -74,7 +74,7 @@ Icon sizes are given as heights to make it easier to append them horizontally.
 In the following example, applying @racket[load-icon] is equivalent to @racket[(plt-logo 100 'diffuse)]:
 @interaction[#:eval icon-eval (load-icon "logo" "plt-logo-diffuse" 100)]
 
-(In the interactions window, you would have to send the result of applying @racket[load-icon] to @racket[icon->pict] to see it.)
+(In the interactions window, you would have to send the result of applying @racket[load-icon] to @racket[bitmap] to see it.)
 
 @doc-apply[icon-categories]{
 Returns a list of all the icon categories.
@@ -221,36 +221,33 @@ A contract that identifies icon styles.
 
 It is more flexible, but a little more complicated, to load icons as @racket[pict]s.
 As picts, icons can easily be appended, inset, superimposed, blurred, and more.
-
+Almost all of the functions in preceeding sections are defined in terms of the @racket[pict]-producing functions documented in this section.
-To use these functions effectively, you should require @racketmodname[icons] and @racketmodname[slideshow/pict] together.
-
-Almost all of the functions in preceeding sections are defined in terms of the functions documented in this section.
 
 @interaction-eval[#:eval icon-eval (require slideshow/pict)]
 
-@doc-apply[load-icon-pict]{
+To use these functions effectively, you should require @racketmodname[icons] and @racketmodname[slideshow/pict] together.
-Corresponds to @racket[load-icon]. In fact, @racket[load-icon] uses @racket[load-icon-pict] to load the icon as a @racket[pict], and passes it to @racket[pict->icon].
+Use @racket[bitmap] to convert a @racket[bitmap%] (e.g. an icon) to a @racket[pict], and @racket[pict->bitmap] to convert back.
-}
 
-@doc-apply[icon->pict]
+Converting from @racket[pict]s to bitmaps can be lossy. For example, converting text can look especially horrible:
-@doc-apply[pict->icon]{
-Convert from an icon to a @racket[pict], and back.
-
-The conversion from @racket[pict]s to icons can be lossy because it renders vector graphics as a bitmap. For example, converting text can look especially horrible:
 @interaction[#:eval icon-eval
                     (scale (text "Hello" null 10) 5)
-                    (scale (icon->pict (pict->icon (text "Hello" null 10))) 5)]
+                    (scale (bitmap (pict->bitmap (text "Hello" null 10))) 5)]
 
-Therefore, when composing icons from parts, work only with @racket[pict]s, and convert to an icon as the last step.
+Therefore, when composing icons from parts, try to work only with @racket[pict]s, and convert to an icon using @racket[pict->bitmap] as the last step.
 
-On the other hand, @racket[(compose pict->icon icon->pict)] always returns an equivalent icon:
+When composing icons from parts, it is fine to use @racket[pict]s converted from @racket[bitmap%]s.
+Without scaling or rotating, the conversion is lossless:
 @interaction[#:eval icon-eval
                     (define not-blurry (magnifying-glass-icon 'green 64 'shiny))
                     not-blurry
-                    (define still-not-blurry
                     (for/fold ([icon not-blurry]) ([i  (in-range 30)])
-                        (pict->icon (icon->pict icon))))
+                      (pict->bitmap (bitmap icon)))]
-                    still-not-blurry]
+
+Avoid converting between @racket[pict]s and @racket[bitmap%]s more than once if bitmap-backed @racket[pict]s are scaled, rotated by angles that are not multiples of 90 degrees, or superimposed or appended at non-integer coordinates.
+Avoid scaling up in general.
+
+@doc-apply[load-icon-pict]{
+Corresponds to @racket[load-icon]. In fact, @racket[load-icon] uses @racket[load-icon-pict] to load the icon as a @racket[pict], and passes it to @racket[pict->bitmap].
 }
 
 @doc-apply[go-icon-pict]
@@ -360,5 +357,5 @@ For convenience, write functions to load the icon; for example,
                   height))
                                                                             
 (define (silly-walk-icon color height [style (default-icon-style)])
-  (pict->icon (silly-walk-icon-pict color height style)))
+  (pict->bitmap (silly-walk-icon-pict color height style)))
 ]

collects/icons/tests/icon-tests.rkt

@@ -75,7 +75,7 @@
                        3/4))
 
 (define not-blurry
-  (let* ([1x   (compose icon->pict pict->icon)]
+  (let* ([1x   (compose bitmap pict->bitmap)]
          [2x   (compose 1x 1x)]
          [4x   (compose 2x 2x)]
          [8x   (compose 4x 4x)]

collects/scribblings/slideshow/picts.scrbl

@@ -1074,6 +1074,12 @@ Draws @racket[pict] to @racket[dc], with its top-left corner at offset
  (@racket[x], @racket[y]).}
 
 
+@defproc[(pict->bitmap [pict pict?])
+         (is-a?/c bitmap%)]{
+
+Returns a @racket[bitmap%] with an alpha channel, no larger than @racket[pict], with @racket[pict] drawn on it in the top-left corner (@racket[0], @racket[0]).}
+
+
 @defproc[(make-pict-drawer [pict pict?])
          ((is-a?/c dc<%>) real? real? . -> . void?)]{
 

collects/slideshow/pict.rkt

@@ -7,8 +7,9 @@
                       [pin-line t:pin-line]
                       [pin-arrow-line t:pin-arrow-line]
                       [pin-arrows-line t:pin-arrows-line])
-           (only-in racket/draw dc-path%)
+           (only-in racket/draw dc-path% make-bitmap bitmap% bitmap-dc%)
-           (only-in racket/class new send))
+           (only-in racket/class new send make-object is-a?/c)
+           racket/contract)
 
   (define (hline w h #:segment [seg #f])
     (if seg
@@ -200,6 +201,16 @@
              (standard-fish w h direction color eye-color open-mouth))])
       standard-fish))
 
+  (define (pict->bitmap p)
+    (define w (pict-width p))
+    (define h (pict-height p))
+    (define bm (make-bitmap (max 1 (inexact->exact (ceiling w)))
+                            (max 1 (inexact->exact (ceiling h)))))
+    (define dc (make-object bitmap-dc% bm))
+    (send dc set-smoothing 'smoothed)
+    (draw-pict p dc 0 0)
+    bm)
+
   (provide hline vline
            frame
            pict-path?
@@ -262,4 +273,6 @@
                        standard-fish
 
                        find-pen find-brush)
-           (rename-out [fish standard-fish])))
+           (rename-out [fish standard-fish])
+           (contract-out [pict->bitmap (pict? . -> . (is-a?/c bitmap%))])
+           ))